Internal combustion piston engine



Sept. 15, 1959 SCHERENBERG ETAL INTERNAL COMBUSTION PISTON ENGINE FiledMarch 23, 1954 ,8 27 30 :6 2a (2a J: 29 32 3 35 35 /3 a u 3" 2a m 3 8 Im 2/ INVENTORS.

HANS 0.5CHERENBERG 8 RUDOLF E. UHLENHAUT.

. ATTORNEYS.

air intake duct.

States Patent INTERNAL COMBUSTION PISTON ENGINE Hans 0. Scherenberg,Stuttgart-Heumaden, and Rudolf ,E. Uhlenhaut, Stuttgart, Germany,assignors to Daimler-Benz .Aktiengesellschaft, Stuttgart-Unterturkheim,Germany Application March-2s, 1954, Serial No. 418,194 Claims priority,application Germany March 26, 1953 14 Claims. (Cl. 123-140 Our inventionrelates to an internal combustion piston engine of the type in which thefuel is injected into the cylinder, preferably during the compressionstroke of the piston for compression and subsequent ignition by a sparkplug. More specifically, the present invention is concerned with themeans for controlling the admission of air and fuel to the cylinder.

In engines of this type, the temperature has a considerable influence onthe ratio measured by weight of the air charge to the quantity of fuelinjected into and mixed with such air. at the instant of ignition.

This influence is of a dual nature: On the one hand, the specific weightof the air charge and thus the number of oxygenmolecules per space unitvaries as the temperature changes so thatcold air will result in a moremeager mixture thanwarm air if the pressure of the air charge and thequantity of the fuel injected per ignition remain constant. On the otherhand, the temperature of the walls contacted by the combustion air is ofcontrolling influence, because it will influence the temperature of theair charge prior to the ignition and it may cause a smaller or largerproportion of the quantity of fuel injected to condense on the walls andto be thus absent in an ignitable form within the air charge at theinstant of ignition.

'In'piston engine of the type to which the present invention relates,there are provided an adjustable control member coordinated to the fuelpump and adapted to variablydetermine the quantities of fuelintermittently injected into the cylinder and a main throttle valve inthe Moreover, there are means responsive to the adjustment of the mainthrottle valve and adapted to adjust the pump control member.Consequently, when the adjustment of the main throttle is altered tothereby vary the pressure and consequent weight of the air charge, thequantity of fuel injected is varied accordingly so as to keep the ratioof mixture at an optimum value.

More. particularly, the means responsive to the adjustment of the mainthrottle valve includes a linkage connecting 'the'main .throttle valveto the control member. Alternatively, the means responsive to theadjustment of the main throttle valve may comprise a vacuum-responsivediaphragm or piston connected to the adjustable pump jected to thevacuum prevailing in the intake duct, such vacuum depending on theposition of the main throttle valve which, as a rule, is formed by abutterfly valve. It is the object of the present invention to provideimproved means for controlling the air charge in relation to thequantity of fuel injected into the cylinder preparatory to any ignition,such control to be effected in de- 2,904,025 Patented Sept. 15, 1959pendence on the temperature so as to avoid any undesired influence ofthe temperature onthe ratio of the air-fuelmixture.

More specifically, it is an object of the present invention to providean auxiliary air throttle valve controlled by temperature-responsivemeans so as to automatically adjust the desired ratio of theair-fuel-mixture when the temperature of the combustion air and/ or ofthe walls contacted thereby changes.

Further objects of the invention are to provide an auxiliary airthrottle valve for easy adjustment by the temperature-responsive meansso that the latter must produce a slight force only for effecting theadjustment, as distinguished froman arrangement in which thetemperature-responsive means are effective to adjust the fuel pump and,therefore, must produce a powerful adjusting force. Expressed in otherwords, it is the object of the present invention to effectuate atemperature control by means of a simple thermostat of the bi-metaltype.

Further objects of the invention are to minimize the reaction of theauxiliary throttle valve on the vacuum tap connected with thepump-adjusting diaphragm chamber, and to minimize the dimensions of theauxiliary throttle valve.

Further objects of the present invention will appear from a detaileddescription following hereinafter of a number of embodiments of thepresent invention, and the features of novelty will be pointed out inthe claims. It is to be understood, however, that such detaileddescription serves the purpose of illustrating the invention rather thanthat of limiting the same. In the drawings,

Fig. 1 shows a more or less diagrammatic axial section through acylinder of an internal combustion piston engine provided with a fuelinjection pump and a main throttle valve in the intake duct, means beingprovided to control the quantity of fuel injected at any time in directdependence of the position of the main throttle valve,

Fig. 2 is a sectional view similar to that of Fig. 1 of an internalcombustion piston engine differing from that shown in Fig. l in that thequantity of fuel injected at any time is controlled in indirectdependence of the position of the main throttle valve, both examples ofthe invention shown in Figs. 1 and 2 being characterized by thedisposition of a thermostat-controlled auxiliary throttle valve in theintake duct,

Fig. 3 is a view similar to that of Figs. 1 and 2 of an internalcombustion piston engine difiering from that shown in Fig. 2 by thedisposition of the thermostat-controlled auxiliary throttle valve in abypass duct communicating with the main intake duct,

Fig. 4 is an axial section taken through the outer end of the intakeduct provided with the main throttle valve and with an auxiliarythrottle valve in form of a needle valve disposed in a bypass duct, and

Fig. 5 is a view similar to that of Figs. 1 and 2 of an internalcombustion piston engine in which the thermostate controlling theauxiliary throttle valve is responsive to the temperature of both thecombustion air and the cooling liquid.

The internal combustion piston engine comprises a cylinder block '10including four cylinders provided with a cooling jacket 11 and with acylinder head 12 which has intake ducts 13 controlled by intake valves14 and outlet ducts :15 controlled by outlet valves 16. The cylinderhead is provided with a lateral bore located adjacent to the compressionspace 17 and adapted to accommodate a fuel injection device 23 of anysuitable type which is connected by a fuel pipe 18 to one of the fouroutlets "19 of a fuel pump 20, one outlet being provided for eachcylinder of the engine. The pump 20 is geared to the customary cam shaftcontrolling the valves 14 and 16, the cain shaft being geared in itsturn to'the'crankshatt actuated by the piston 21 through theintermediary of a connecting rod 22. The fuel pump feeds intermittentlyquantities of fuel to the injection deviee23ofeach cylinder and'issotimed that the injectionof the fuel takes place while the'intake valve14 is open and the piston 21 sucks air into the cylinder thrQ i'gh theintake duct '13.

'The intake duct '13 communicates with an inlet duct 24 'in which amain'throttle valve inform of a'butterfly valve 25 is inserted.

epump is provided with an adjustable control member in form of a controlrod 26which,'for' the purpose of varying the quantities of fuel, isshiftably mounted 'i'njih pump 20 in the direction of its axis.

The power produced by the engine may be controlled 'by a'threje-armedlever '27 having one'arm provided with ahandle 28 and adapted to berocked'about a stationary ftilcriim 29. Another arm of lever 27 isconnected 'by 'alink to the control rod 26, and a third of the lever 27'is connected by a link 31 to an arm-32 "fixed to the outer end'of theshaft of the butterfly valve 25. Ifdesired, lever 27 may be connectedwith a governor. When the'handle 28'is depressed to reduce the poweroutput of the internal combustion piston engine, the throttle is movedtowards its closed position, whereby the weight of the air chargeadmitted into'the cylinder 10 is reduced. By the same adjustment of thethreea'rnied lever 27 control rod 26 is moved to the left, whereby thefuel'quan'tities intermittently fed by pump 20 through pipe 18 to theinjection device '23 are rediiced accordingly to thereby keep the ratioof mixture ofair and fuel'constant irrespective of the power output. y

Thus, it will appear that the linkage 31, 27, con- 'necting the mainthrottle valve '25 to the control member 26 eonstitut'es, in effect, ameans which is responsive to the adjustment of the main throttle valve25 and is adapted to" adjust the control member 26.

For the purposes of the present invention we have providd an auxiliarythrottle valve which may take the form of a butterfly valve '33 mountedin the inlet duct 24, and we have furthermore providedtemperature-responsive means in form of'a thermostat 34 of the bi-metaltype, the movablearm 35 of the latter being connected by a link '36 toan arm 37 fixed to the outer end of the shaft of the butterfly valve 33,the latter being so adjusted thatit is adapted to unthrottle the flow ofair through the'inlet duct 24 and the intake 13 intothe-cylinder 10'when the temperature of the thermostat 34 increases. In the embodimentshown the thermostat member '34 is mounted in a bore provided in thewall of duct 24, and its temperature-sensitive element 38 projectsintothe duct 24 to be subjected to the flow of air-therethrough.

Hence, the temperature-responsive means is mounted to respond to thetemperature of the air sucked into the inlet duct 24.

The operation of the controlling system is as follows:

A'predetermined position of the main throttle valve 25 and of theadjustable control member 26 is allotted to any position of lever 27. Inthis manner, such quantity Qt'fuel will be injected into the cylinder 10for any ignition as corresponds to'the weight of the air chargedetermined by the position of the main throttle valve 25.

Should the temperature of the air drop, the auxiliary throttle 33will beso turned as to increase its throttling efiect upon the flow of'airthrough the inlet duct 24. As 'a' result,the volume of the air chargesupplied to the cylinder 10 will 'be somewhat reduced without affectingthe quantity of fuel injected. Under normal conditions, the throttlingeffect produced by the auxiliary throttle valve 33-can be 'so selectedthat the weight of the air charge supplied to the cylinder 10 for anyignition will remain constant, thus ensuring an invariable ratio ofmixture of fuel and air. Should the'temperature of the air flo'wingthrough inlet duct 24 'rise, the auxiliary throttle valve 33 will be soadjusted by the temperatureresponsive means 34 as to 'unthrottle theflow'of air.

The embodiment of the t-present invention illustrated in Fig. 2 isidentical with that shown in Fig. 1 in many respects, and, therefore,the same reference numerals have been applied to the correspondingelements. This embodiment, however, differs from that shown in .=Fig. bythe absence of the lever 27, the controlmember 26 being connected 'to amovable"wall*member,"suchasfa diaphragm 39, ofla'vacuum chamber 40connected by a tapping pipe 41 with the inlet duct 24 'at a'point42vwhere the vacuum prevailing in the duct 24 depends on the positionofthe main throttle'valve 25.' Therefor-efithe vacuum prevailing-at thepoint 42;depending on the position of the throttle valve 25 will betransferred to the vacuum chamber 40. Depending onthe degree of suchvacuum, the diaphragm 39 will be bent thereby adjusting control member26 accordingly. In this manner, the quantity of fuelinjected willincrease 'when'the absolute amount of' the pressure prevailing in theinlet-ductfl at the point42increases. Thus, vthedi'aphragm"39constitutes a meansrespons'ive'to the adjustment-ofthemai'nthrottle valve 25 andadaptedto'adjustthe control member '26. i

A third embodiment of the'prese'nt'invention is illustrated in Fig. 3which'in'many respects is identical with that shown'in Fig. 2,asindicatedby theuse of the same reference numerals for thecorresponding elements. Thus, the controlmember 26 isadju'sted by adiaphragm 39 of a vacuum chamber'40 connected to apoi'ntf42 of inletduct 24 by a pipe 41. I-Iov'vever, thisembodiment differs from thatshown in 'Fig. j2by'the disposition of the auxiliary throttle'valve;Thisjauxiliar'y'thiottle valve 333 is contained in a'n-aiixiliary duct"43 which bypasses the main throttle valve 25 preferably br'anchesofi theinlet duct '24 at a'poi'nt'44 located outside the'main throttle valve25. Alternatively, however, duct qs'may open'into'the atmosphere at anydesired point. The exterior end of the shaft of the. throttle 'va1 ve333 has an arm 337 which is connected'by a link 336 to the 'movable endof the thermostat 334, the arrangement i'bein'g such that acontraction'of the temperatiire responsi've'ele; ment 334 caused by adrop of the temperature of thefair passing through duct '24 will'throttleduc't 43 "thereby reducingthetotal volume of air's'uckedintocyliiider 10 through both of the'ducts 24and43.

The embodiment illustrated infFig. 4v is 'similar in many respects'tothat shown inFig. 2' differing therefrom, however, by'the absence of'thebutterfly [van e33 and by the provision of the followingmeans:"The'pipe 41 leading to'th'e diaphragm ohambe'r'40communicateswith a radial bore "45 provided'inthe wall ofthe inltduct '24 leading topoint-42 which, ssailedabove, 'is 'located between the main throttlevalve 25 and the 'intake'13 of the engine. Bore 45has a'bran'ch'4'6i'which themain throttle valve 25 leading to abore47"comm'unieating-With the atmosphere, forihstance' at a 48"of duct24 outsideof main throttle'valve '25. Theboi'e'j' t l is provided withavalves'eati'coope'rating Witha needle valve 433fvv'h'ereby the newerthrough meanes and 46 maybe rammed. '"Ntwo' aimedflever'fiilcrunied on abracket 50 rigid with'the'wallof duct 24 has 'one arm 49 connected tothe'inovable"end of a bifmetal'thermediate those'pressures which prevail'at'th'e points 42 and 48. Therefore, thevacuumin pipe 41jisless'povvertul than that prevailing at fthe'point 42 I Whenthe'tempeiiat e i r e t sii ifiist istre ilt i ltl asstat 434 wil lcontract rocking lever 49, 51 anti-clockwise, whereby bore 47 will beunthrottled thereby further reducing the vacuum in pipe 41. As a result,the control member 26 is shifted to the right thereby increasing thequantity of fuel injected in proportion to the increase of theweight ofthe air charge, the latter increase being due to the drop of thetemperature of the air. Hence, it appears that the bores 46 and 47constitute an auxiliary duct which bypasses the main throttle valve 25and contains the auxiliary throttle valve 433.

' Fig. shows an'alternative disposition of the temperature-responsiveelement, the same being formed by a bi-metal thermostat 534 mounted inthecoolingjacket 511 of the cylinder head, its temperature-responsivemember 538 extending through a bore in the lower wall of the intake 13-so as to be responsive to both the temperature of the cooling mediumcirculating through the jacket 511 and to the temperature of the airflowingthrough inlet duct 24 and the intake 13. Otherwise, theembodiment shown in Fig. 5 may be similar to any one of those describedwith reference to Figs. 1, 2, 3 and 4, a suitable linkage 536 being'provided to connect the movable element of thermostat 534 to theauxiliary throttle valve 33 or 333 or 433.

While We have described our invention with reference to'a number ofspecific embodiments thereof, we wish it to be clearly understood thatthe same is capable of numerous modifications within the scope of theappended claims and is in no way restricted to the details shown. Thus,the injection device 23 need not be located at the point illustrated.

What we claim is: n 1

1. In an internal combustion piston engine, the combination comprising acylinder, a fuel injection device mounted to inject fuel into saidcylinder, inlet and outlet valves mounted on said cylinder, an inletduct controlled by said inlet valve, a fuel pump geared to the engineand connected with said injection deviceand adapted to intermittentlyfeed quantities of fuel to said injection device, a main throttle valvein said inlet duct, an adjustable control member operatively connectedto said pump and'adapted to variably determine said quantities of fuel,means responsive to the adjustment of said main throttle valve foradjusting said control member, means in said engine responsive only totemperature changes within said engine that are proportional to thetemperature of the air fed to the cylinder, an auxiliary throttle valvecontrolled by said temperature-responsive means to vary the air chargeadmitted to the cylinder through said duct in relation to said quantityof fuel when said temperature changes.

2. The combination claimed in claim 1 in which said means responsive tothe adjustment of said main throttle valve includes a linkage connectingsaid main throttle valve to said control member.

3. The combination claimed in claim 1 in which said means responsive tothe adjustment of said main throttle valve comprises a chamber having amovable wall member connected to said adjustable control member and aconduit connecting said chamber to said inlet duct at a point where thevacuum prevailing in said =duct depends on the position of said Imainthrottle valve.

4. In an internal combustion piston engine, the combination comprising acylinder, a fuel injection device mounted to inject fuel into saidcylinder, inlet and outlet valves mounted on said cylinder, an inletduct controlled by said inlet valve, a fuel pump geared to the engineand connected with said injection device and adapted to intermittentlyfeed quantities of fuel to said injection device, a main throttle valvein said inlet duct, an adjustable control member operatively connectedto said pump and adapted to variably determine said quantities of fuel,means responsive to the adjustment of said main throttle valve foradjusting said control member, means in said engine responsive only totemperature changes 6 within said engine, an auxiliary throttle valvecontrolled by said temperature-responsive means and adapted to vary theair charge admitted to the cylinder through said duct in relation tosaid quantity of fuel when said temperature changes, saidtemperature-responsive means being mounted in said engine to respond tothe temperature of the air sucked into said inlet duct.

5. The combination claimed in claim 1 in which said means responsive tothe adjustment of said main throttle valve comprises a chamber having amovable wall member connected to said adjustable control member and aconduitconnecting said' chamber to said inlet duct at a point where thevacuum prevailing in said duct depends on the-position of said mainthrottle valve, said auxiliary throttle valve beingdisposed in 'saidinlet duct-between said point and said inlet valve.

I 6. The combination claimed in claim 1 in which said inlet ductcommunicates with-an auxiliary duct bypassing said main throttle valveand containing said auxiliary throttle valve.

7. The combination'claimed in claim 1 in which said means responsive tothe adjustment of said main throttle valve comprises a chamber having amovable wall member connected to said adjustable control member and aconduit connecting said chamber to said inlet duct at a point where'thevacuumprevailing in said duct depends on the position of said mainthrottle valve, and in which said inlet duct between said point and saidinlet valve communicates with an auxiliary duct bypassing said mainthrottle valve and containing said auxiliary throttle valve.

8. The combination claimed in claim 1 in which said means responsive tothe adjustment of said lmain throttle valve comprises a chamber having amovable wall member connected to said: adjustable control member andaconduit connecting said chamber to said inlet du'ct at a point Where thevacuum prevailing in said ductdepends on the position of said mainthrottle valve, and in which said inlet duct between said point and saidinlet valve communicates with an auxiliary duct which bypasses said mainthrottle valve and contains said auxiliary throttle valve and branchesoff said inlet duct at a point outside of said main throttle valve.

9. In an internal combustion piston engine, a cylinder, 2. fuelinjection device for injecting fuel into said cylinder, inlet and outletvalves mounted on said cylinder, an air inlet duct controlled "by saidinlet valve, a=fuel pump geared to the engine and connected with saidinjection device and adapted to intermittently feed quantities of fuelto said injection device, a main throttle valve in said inlet duct, anadjustable control member operatively connected with said pump tovariably determine said quantities of fuel, vacuum-responsive meansconnected to said control member for the adjustment thereof, a conduitconnecting said vacuum-responsive means to a point of said inlet duct,said conduit being provided with an inlet port, a control valvecontrolling said inlet port, and temperature-responsive means in saidengine responsive only to temperature changes within said engine thatare proportional to the temperature of the air fed to the cylinder andconnected with said control valve to throttle said inlet port when thetemperature increases.

10. In an internal combustion piston engine, a cylinder, a fuelinjection device for injecting fuel into said cylinder, inlet and outletvalves mounted on said cylinder, an air inlet duct controlled by saidinlet valve, a fuel pump geared to the engine and connected with saidinjection device to intermittently feed quantities of fuel to saidinjection device, a main throttle valve in said inlet duct, anadjustable control member operatively connected with said pump tovariably determine said quantities of fuel, vacuum-responsive meansconnected to said control member for the adjustment thereof, a ductconnecting said vacuum-responsive means to a point of said inlet ductlocated downstream of said main control valve, said duct being providedwith an inlet port tenminating Q in,;'said;duct upstream of said maincontrolvalve, a fureontrol valve controlling said .-inletvporhsand-temprimate-re pon ive means in. i eng neconne t .iBSiQg'WI'xCODiIOl.'VBlW/6 to throttle said, inlet port lpon increases in:temperature within said engine that are proportional ,to the@temperature efthe air fed .to the cylinder. 1 II n. 1-1xIn-'an.-imemalcombustionv piston engine, the'comv'comprising a cylinder, -a -fuelinjection devicev mounted toln'jcet :fuel into .said cylinder, inlet andoutlet; valves mounted on said :cylinder, an inlet duct con-,trollodbysaid ,i'nlet. valve,,-a*fuel pump geared tothe connected withsaid injectiondevice and adapt c'dato. intermittently Efeed quantitiesof fuel to said injecv tiohldevice, a mainathrottle valvein said,inlet-duct, an adjustable control member-nperativelyconnected to saidpump and adapted. to, variably determine said. quantities obfuel, meansresponsiveto the adjustment-of said rnain throttle valve for adjustingsaid :control. member, means in said engine responsive only totemperature changes within'sdid engine, anauxiliarythrottle.valve-controlled byn'said."temperature-responsive.means and adapted to vary the xair oharge admitted to the cylindervthrough said ductnin relationto said quantity of fuel when saidtemperature changes, said ftemperature-responsive, means beingmountedlin said engine to respond to the temperaturecftihe wallofsaidinlet duct. 12. Iran internal co'mbustionrpiston engine having acoolingjackt thro'ughwhich a :coolingmedium circulates,- thecombination.- comprising arcylinden; a fuel injection idevicc mounted.to inject fuel into said cylinder, inlet'andzoutlet valves imounted onvsaid. cylinder, an inletiductcontrolled'bysaid inlet'valve, afuel-'pump'geared toirhe engine.-and.connected.:v vith' said injectiondevice and. adapted :to intermittently, 'feed,;quantities .of fuel .tosaid injection device, a mainthrottle valve in said inlet ductganadjustable co'ntrol member operatively connectedkto said' pumpandadapted to variably determine said 'qixantitiesqof fuel, meansresponsive to the adjustment ofv'said main throttle valve for adjustingsaid control number, means in said engine responsive only -totemperature changes within said; engine, an auxiliary throttlevalves-controlled. by said temperature-responsive "means and adapted -tovary the-air charge admitted. to the cylinder 'through said' ductinrelation to said quantityof fuel when said temperature changes, saidtemperature-responaive means being mounted to respond to the temperatureof saidcoolin'g-medium.

13.5111 an internal combustion piston engine, the'combinatidncomprisinga cylinder, a -'fuel injection device moimted -to inject -fuel into.said cylinder, inlet and outlet-valves mounted; on said cylinder, .an-inlet duct contIOllQdfiby said-inlet yalve,;a fuel ;pump geared -to theengineandconnected with saidinjectiondevice and adapt ed tointermittently iced quantities {Of -;f;l1 LtO said-injection device, amain throttle ,valve in sa d inlet duct, an adjustable control memberoperatively connected to said p mpa a ap dnv a y determine d quan ti sof fuel, means-responsive to the adjustment of said main throttlevalveior, adjusting said control member, means in said engine responsiveonly. to temperature changes Withinsaid engine, an auxiliary throttlevalve controlled by. said temperature-responsive means and adapted to ythe 1; air; cha g admitted t h tcy nde thr said -duct in-relation tosaid, quantity of fuel when said temperature changes, :sai'dtemperature-responsive means being a thermostatic element responsive totemperature changes only and exposed to the-air flowing in said inletduct. v

-14. Inqan internal combustion piston engine having a cooling jacketthrough which a cooling medium circulates, =the-combination comprising acylinder, a fuel injection device mounted to -injectv fuel into saidcylinder, inlctrand'outlet valves mounted on 'saidcylinder, aninlet ductcontrolled by said inlet valve, 21 fuelpump geared -to the engineand-connected with said injection device and adapted tointermittently-feed quantities of fuelto injection-device, amainthrottle valve in said inletduct,v

anadjustable'control memberoperatiyely connected to said pump andadapted to variably determine said quantities of fuel, means responsive-to the adjustment of said main throttle valve for adjusting saidcontrol member, means in said engine responsive only to temperatureohangesrwit-hin said engine, an auxiliary throttle valve controlledby,saidtemperature-responsive means and adapted to =vary=theair chargeadmittedto the cylinder through said duct. in relation to said quantityof fuel when said temperature changes, said temperature-responsive meansbeing mounted to respond'to the temperature of both said cooling, mediumand the, air flowing through said inletqduct'. v v

-Referen ces Cited in the file of this patent UNITED STATES PATENTS I'OTHER "REFERENCES Serial No. 376,679, Fuscaldo (A. P.C.),. -publishedMay 11, 1943.

